Electron beam deflection and rebalancing apparatus



Oct. 7, 1952 W H. KLJEVER 3 ELECTRON BEAM DEFLECTION AND REBALANCING APPARATUS Filed June 28, 1948 CONfiiOLLI NG MEMBER v 2/ 25 -E 9' y A 25 *f L Zhwentor The present invention [a system whereby a novel tatable abdut UNITED STATES PATENT r ELECTRON BEAM DEFLECTION AND REBALANCING APPARATUS Waldo H. Kliever, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn, a corporation of Delaware Application June 28, 1948, Serial N 0. 35,614

1 relates generally to that type of apparatus for deflecting and rebalancing beams and in particular to that type of apparatus for deflection of. the beam ina cathode ray tube and the rebalancing of the output of the tube. I

It isan object of this invention to provide such mag-net of simple construction produces deflection in accurate propor tion to the extent of the controlling condition.

v Another object is to provide such a system wherein the magnet is rotatable about the normal axis of the electron beam, v I Another, object is to provide such a system wherein the magnet is rotatable in a, plane normal to the normal axis of the electro beam. a

Another object is to provide such a system wherein the magnet may be endlessly rotatable. e "One manner by which I accomplish the above objects is by using an endlessly rotatable circular permanent magnet having two inwardly extending pole pieces. This circular v,rnagnet is placed around the tube in which an electron beam to bede'flected, v I The'above mentioned objects may also beaccomplished, in accordance withmy invention, by

positioning a barmagnet at theend of the oath;-

ode ray, tube beyond the termination of the electron beam, said magnet beingendlessly r0.-

about thenormal axis of ther;;electron beam. Another object of the invention is todprovide novel means for reducing the signal senttoa fload means to zero by rotatingthe tube about the normal axis of the electron beam inthe tube. .The energizing signal for rotating the tube may be obtained fromtheoutput of the tube plates. pecific forms which the systems embodying the invention maytake are shown in the accomfpanying drawings in which: I I I Figure 1 is a modification of the invention disclosing a circular endlessly rotatable magnet 'a cathode ray tube and a feedback circuit for'rotating the tube,

I Figure 2 is a modification disclosinganbther mannerof rebalancing the apparatus,

-Figure 3'is a modification disclosingthe use of an endlessly rotatable bar magnet to deflect the beam and still another manner ofrebalancing, and V I I I. a Figure 4 is aviewtaken along the line I-.-fi vin Figure 1 showing the shape of the circular magnet and 1 its position withrespect to the cathoderaytube v I I I V, l

Species of Figure 1 In Figure l isshown a cathoderay tube I having a filament. heating a cathode I2. An electron gun I3 controlsthe beam I and directs it toward the two target plates Handle-I3. The

1 12 c aims. (or 318 28) beam I4 is modulated by means of an alternating voltage impressed between the cathode I2 and electron gun,l3. The alternating voltage is sup- ,plied by a transformer having a primary 2I and a-secondary 22. The primary Zl of transformer 20" is energized from power leads 23 and 24 through leads25 and 26.

A battery 33 energizes the cathode raytube by impressing ,a voltage between the plates I5 and I6 and the cathode I2. A portion of the battery is also'used to place a positive potential on the electro gun I3 with respect to cathode by the following circuit; cathode I2; lead 3|, transformer secondary 22, that portion ofbattery 30 between transformer secondary 22 and terminal 32, lead 33, and electron gun I3. The potential applied between the plate I5 and the cathode I2 is by the following circuit; cathode I2, Ilead'3I, transformer-secondary 22, battery 30, lead, resistor 35, lead 36 and plate I 5. The potential impressed betweencathode I2 and plate lo is by the following circuit; cathode I2, lead 3|, transformer secondary 22, battery 30, lead '34; resistor-31,1ead38 andplate I6.

A controlling member Mis connected bya mechanical drive H to a gear 42. The controlling member may be either manually operated or operated by some condition responsive element such, for example, as abimetallic element. Thegear 42 meshes with segments on the outer edge of a circular.magnet 43, better shown in Figure 4.

In Figure l the circular magnet 43 is shown I surrounding the envelope I0 on the cathode ray :northand south magnetic terminals. and" described magnet 43 is a permanent magnet. The controlling member could be capable of tube. Two'inwardly projecting portions 44 "and 45 of the magnet are :shown,.these being the As shown continuously rotating gear 42 and thus magnet 43.7 Means for mounting the magnet 43 are shown in Figure 4 as two guiding rollers 46 and 41 which are, with gear 42, spaced about magnet to support the magnet about the. tube It is understood, however, that the supporting means may be any means commonly used for mounting an endlessly rotatable circular member about another i The output of the cathode ray tube is applied from plates I5 and I6 through the leads 3B and 50 and leads 38 and 5I to amplifier 52. This amplifier maybe any amplifier suitable for taking two signal inputs, comparin them, amplifying the diiference in signals, and supplying an output reversible in phase toone winding of a reversible .motor. 1 A suitable amplifier for this purpose is shown in an Upton Patent 2,423,534 having the .same as'signee as the present application. w The ground II. permits electrons to -flow in same, assignee'as the present invention. 1

to zero there will be acisgsco and that it has been .shown jplacedJ-beyond. the target Iplates merely .foravconvenienceh. .The

1 amount of deflection of 'theielectronbeam Ilvdue to the I, magnet is dependent" upon :the J distance of'thelsmagnet from the cathode, This is :true because .the closer; the magnet .isito the cathode the greaterithe .deflectioniof (the, beamiwimme: diat'ely upon leaving the, cathode; The banmag-w fnetxI I isfconnected to a controllingwmember ;I I I through a mechanical connection] I 2' and is ,also

endlessly rotatable as I is 'the icircular g. magnet; 43

shown in Figures l and 2n? .The bar-magnet, I I 0 has the same effect. upon the? electron;,beam I4 -as does the circular. magnet 43;; Inthis species "of the-invention, a" coil II I is:employed to deflect. the beam toirebalance the-,system This :coil is connected to the output terminals of; am.- plifierv 58 by. a circuit including'anammeter. I I

In the position shown theimagnetdfll willjcause the electron beam I I-to bedeflected, to. the right,

abut. the-beamlll will still be proportionedequally between the plates I5;'and .l 6. Asa result no signal willbe sent from;1the platesto thewam-jpowerusourceyand an-I'ALQ. signal to producean C. output the amplifler 58I in Figure 3 uses ;'an; A-. ,C. power -source and: 2 :1 A .C 'signalgto pr du e a D- 0. out ut: o var ab e. ma nitude .It, is to. be understood that the: output 1f amplifier58 may be reversed in polarity; n ampl e w h l a enth s purpose is shown n at Wills P nt 2. .5.6304 a das sn d othe I If e m t H1 s rot d-s ht y-t accr} responding deflection of the beam; I Q, will cause a greater portion of the beam to impinge upon one'of the platesand a lesser portion of the beam to impinge upon the other plate, thus causing a signal input ,to' theamplifier 58. The output of the amplifier willbe applied through leads H3 and H4, indicator amnieter H5, and lead o a b an n o 1 IL. n in coil I I I remains fixed" in positionfbut the currentytherethrough is dependent upon the;: un'- balance of the electron beam striking theplates.

Witha small signal input to ,the amplifierflBfi.

' a'smallcurrent will be sent through thejflcoil I I1 which-will send out a weak; magnetic field.

This current willbe determihedby the constants of the amplifier. It is to :benoted, howeventhat if theidefiection of the electron beam becre'du'ced amplifler output to the magnet I II! would again deflect the beam away from-center. was; an ancing coil II'I does not completely reducethe deflection of the beam to zero but rather reduces i' I due to the balancing 0011 411. The ammeter is placed in the balancing tcoil circuit merely to indicate the amount of deflection of "the electron beam, and because of this may haveialdial.cali- 'brated in .terms of the 'beam deflection placed thereon. a I 1 1 It is'to be understood that the invention herein disclosedis not considered to be limited to the modification herein described, but is rather to be limited only to the extent of theuclaims hereto appended. I I I I claim as my invention: 1.1115 combination: means for directing an electron beam alongan axis; target means'disposed about said axis for impingement by said beam; deflecting means having spaced; opposed poles. to provide a directed field to deflect said beam from said'axis to produce a signal. on said target means; means mounting said deflecting means for rotation about an axis perpendicular to'said field and alignedwith said axis ofzsaid beam; and means responsive to acondition'to'be sensed to position said deflecting means inac cordance with the value of said condition. I

"2.. In combination: means for directing 'an electron beam along an axis; target means dis posed about said axisfor impingement'by said beam; deflecting means having spaced, opposed magnetic poles to provide a directed fleldto deflect saidbeam from saidlaxis to produceia signal on said target means; means mounting said deflecting means for rotation about an axis perpendicular to said ifield and aligned with said axis of said beam; and means responsivetoa condition to be sensed to position said deflecting means in accordance with the value of. said con dition. I

3. In combination: ltarget kmeans disposed about an axis for impingement by an electron beam; means for directing said electron beam along said axis to energize said targetJmeans; deflecting means having spaced, opposed poles to provide a directed field todeflect said-beam from said axis'to vary the relative energization I of said target. means in accordancewithithe amount of deflection of said beam fromsaidaxis; means responsive to the change of relative energization of said targetmeans; means mounting said deflecting means for rotation about an axis perpendicular to said field and. aligned with said axis of said beam; and means responsive ,tojja condition to be sensed to position said deflecting means in accordance with the value ofasaid condition. I

; M 4. In combination: target means disposedabout anaxis for impingement by an electron beam; means fordirecting said electron beam along said .ax-istoenergize said target means; deflecting it to the point where that component of the mag- H netic field due to the bar magnet, which is permeans havingspaced, opposed poles to provide a directed field to deflect said beam from-said axis to varythe relative energization of said tare get means in accordance with the amount of deflection of said beam from said axis; means-re.- sponsiveto the, change of relative energization of said target means; followup means .to; restore the ,initial energization of saithqtargeinmeans; means mounting said deflecting. means riorirota tion about an axis perpendiculartmsaid fieldiand aligned-withsaid axis of said bearn and.I means responsive to, a condition tobe sensed to position said deflecting means in accordance with the value of said condition.

5. In combination: means for directing an electron beam along an axis; a plurality of target plates disposed about said axis for impingement 7 Y by said: beam; 'Idefle'ctifig --means .:having spaced. oppo'sedmagnetic poles to'provide adirectedrfleld to; deflect said beamxfrom said-.axiszto produce si'gnals:= of."- difierentgmagnitudes. onsaid target plates; means mounting said deflecting means-for rotation about an axis perpendicular to said field andi'aligned withlsaid axis ofvsaid beamra responsive device electricallyconnectedlto said target plates'to' receive aisignal' therefrom; follow upmean's'; dependent on the signal: to said responsive device, for reducing the signal'to said responsive device to arm'i'nimum; and means responsiveto-a condition' to be 'sens'edto position said deflecting means inaaccordanee with the value of said condition; :1;

. 6'. :'In:combination: means for directing anelectron beamhalongi an axis; .a plurality of target plates adisposed :foriimpingement by said beams;

accircnlar magnet mounted symmetrically about the'zn'ormal axis'of sai-d'beamiinr-a plane normal thereto and endlessly rotatable aboutsaidfbeam forsdeflecting saidl beam to; produce signals of difierent. magnitudes on said; target plates; means rotating, said magnet in response to a condition; aeresponsive device electrically connected to said target :-plate: toreceive a signaltherefrom; and means; dependent-upon thesignal to said responsive deviceto a'minimum.v

- "7'. In combination: means for. directing an electron :beam:alongsan axis, target means disposed aboutisaidaxis for impingement by said beam, deflecting means for'deflectingsaid beam from said axisto produce a'signal on said target 'means',

andtrmeans for; mounting said deflecting means mounting and rotating said deflecting meansj and loa'd means'for' utilizing a signal dependent in magnitude upon" the extent of said unequalimpingem'ent torotate said target plates aroundsaid axis' to' cause the beam to equally impinge on said target plat'es. Y i

9. In combination: means for directing an electron-"beam along an axis; a plurality of target plates disposed about said axis for normally equal impingement by'said beam means for deflecting said b'eam from said axis to produce unequalimpingement "on said target platesj means for mounting said deflecting means symmetrically about the "normal axis of said beam in a plane normal'thereto and endlessly rotating said de-'- flecting-mea'ns" about said axis; and load means 'for htilizing a signal dependent" in magnitude upon the'extent of said unequal impingement to rotate'said target plates around said axis to cause the' beam to equally impinge on said target plates. 1-0. In combination: means for directing an electron beam along an axis; a plurality of target plates disposed about said axis for normally equal impingement byfi idwbeamx acircular magnet r for deflecting said beam from said axis to produce unequal impingement-on said targetplatesymeans for mounting said magnet symmetrically about the normal axis of'said beam ina plane normal thereto and endles'slyrotating said-magnet about said" axisrland load means iforiutilizing a" signal s dependent in magnitude upon. the" extent 01 said unequal impingement to rotate said target plates around said axistocausethebwm to *equallyim pingeonisaid targetplates. 1

"11. In ico'mbinationz' meansror directingan electron beam alonganiaxis; apluralityofxtarget plates disposed about; said axis fort normally equal impingement by said beam; :deflecting to produce a signal by iunequal impingementbn said' target plates;- means for mounting :said derfleeting: means symmetrically about the "normal axis-of said beam in a plane normal thereto beyond the termination or said beam on said target plates; said deflecting means being end:- lesslyrota'tabie about said axis by-means operating in response to-a conditionya'nd" load means 'sive=device,=for-reducing the si'gnal'to said responfor utilizing! a signal dependent in v magnitude upon the extent-oi *said unequal impingement to rotate-furtherma'gnetic means around said axis target" plates to a-minimum.

to reduce the une'qua-l impingement "on-'=-"said In combination: means for directing" an "electron beamalong' an axis: a plurality oit'arget plates'disposed aboutsaid axis" for impingement bysaid beam a circular magnet mounted symmetrically aboutfthej normal axis of said beam in a plane normal thereto and endlessly rotatable about" said axis'j f or deflecting said beam" from said ax ist'o' cause saidbeam to unequally inipinge' "said target plates; means rotating said magnet in response tea conditionfa responsive device electrically connected" to i said target plates toieceive a signal therefrom dependent 'inr'nag nitiide upon the'extent or said unequal imping'ejment; and-means dependentupon thesignal' to said responsive device, is rotate 'said target p1ate's-; arour idasaidaxis to causesaid beam to equally impinge? on said target plates;

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